Over the last two decades advances in the understanding of disease at a cellular and molecular level has led to innovative therapies that are based on the administration of cells which have been modified outside of the body. Ex vivo cell therapy is in essence gene therapy delivered by transfer of therapeutic genes to cells in culture, which are then given to the patient to treat fatal infections such as AIDS, or other conditions such as cancer or genetic diseases. These manipulations include the purification and culture of therapeutic cell subtypes, as well as elimination of cells which cause...